Thanks for the replys.
Sounds like I'm not too far off base with trying up to 3 more degrees.

Carringb,
Forgot to mention it earlier. There are some shims under the leaf pack that look like they are caster shims. I would guess adding some there wouldn't be the best idea and doing the sleeves would be a better idea? Or maybe remove the shims that are there and replace with a single wedge that provides more caster would also be acceptable?

For future reference --- can I ask where you're finding those load/inflation specs?

I looked on BFG's website and was only able to find a downloadable .pdf file that gave "max load/max psi" numbers for each tire, but couldn't seem to find any kind of an indexed/scaled "load vs. pressure" range for each tire size.

Here's one from Toyo. It actually doesn't matter which brand's table you use. Its the Tire and Rim manufacturer's Association that set these ratings. LT tires start on page 22.

Thanks for the replys.
Sounds like I'm not too far off base with trying up to 3 more degrees.

Carringb,
Forgot to mention it earlier. There are some shims under the leaf pack that look like they are caster shims. I would guess adding some there wouldn't be the best idea and doing the sleeves would be a better idea? Or maybe remove the shims that are there and replace with a single wedge that provides more caster would also be acceptable?

Yeah, I'd shoot for 5-5.5. Even a little more is ok for steering precision, but it can increase steering effort at the extremes.

Basically, shims can be used for adjusting caster, but it will change the driveline angle too. If the two need to move in opposite directions, that's when the ball-joint sleeves should be used instead. Also, leaf springs change caster as they sag, so something to keep in mind.

I know Ford does allow stacking shims in the heavy duty trucks, but I'm not sure what their policy is on a driven front axle. I don't really see it any different from adding leafs, but the Four Wheelers guys recommend not going past 6-degrees with shims.

I think toe has a huge effect. Obviously caster needs to be reasonable. My ujoint kit without any shims in front has 3.8 degrees caster, and it drives great IF toe is right. That means having some positive toe. When I set it up in the driveway toed in quite a bit it drove pretty good, but was noisy. Took it for an alignment and it was 1.3 degrees towed in. Obviously that was the reason for the noise. Left with .20 degrees toed in (positive toe) and it was amazing. The "tech" didn't line the adjuster sleeve clamps up with the slits in the tie rod so it jumped off somewhere and sucks again.

Anyway, same thing with my Jeep Wrangler on 35s. Minor toe adjustments made a huge difference. Toed out and the tires are grabbing at every change in the road, pulling while braking. Toed in too much is similar but much less dramatic.

Dial in a little more caster (I'm sure anywhere between 3-5 is fine) with some shims and toe in .30 degrees or so. I bet it does wonders.